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Does fiberglass shrink/compress?

TX7A

Well Known Member
I need to layup 2 or 3 layers of fiberglass cloth to achieve a certain thickness. If I wet-out the glass with resin between plastic sheets and squeegee out the excess, lay it out on the surface & then sponge on peel ply, will the finished thickness be (practically) the same as unwetted glass?
(Apologies for such a long sentence...iphoneing it) :eek:
 
If you are trying for a specific thickness, I would do a bunch of test layups with various numbers of layers to see how thick they are.

I know that on most of the fiberglassing I did on things like the airbox, wheel pants and canopy, you need at least 3 layers to have any real stiffness.
 
BID

For general BID layups I allow 0.013" per layer for a finished part, and this works out just about right if the glass is smooth and you don't oversaturate it with epoxy.

But I've only had to do this a few thousand times, so I could be off a little bit. :)
 
Thanks, Kevin. That's pretty much what I needed to know. I know different weights will result in different thicknesses. I should've done layup tests long ago but didn't. Kind'a strapped for time on this little project I'm working on.
 
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